题目1：设计一个8位数字显示的简易频率计。要求：
①能够测试10Hz~10MHz方波信号；
②电路输入的基准时钟为1Hz，要求测量值以8421BCD码形式输出；
③系统有复位键；
④采用分层次分模块的方法，用Verilog HDL进行设计。
⑤写出测试仿真程序(Topic 1: Design a simple frequency meter with 8 digits display. Requirement:

It can test 10 Hz ~ 10 MHz square wave signal.

(2) The reference clock input by the circuit is 1Hz, which requires the measured value to be output in the form of 8421BCD code.

(3) The system has reset keys;

(4) The design is based on Verilog HDL with the method of hierarchical module.

Write out the test simulation program)